As is known, the ventilation of passageway and/or tunnelways in an underground mine, such as for coal, presents a serious need. Usually, the aforesaid passageways are defined by a grid pattern established by pillars of coal dependent, in part, upon the height of a given seam. As coal is mined, the mining activity becomes more distant from the source of ventilation and, accordingly, it is desirable to selectively pass contaminated air over intersecting air inlet passageways to exhaust.
Importance lies in the fact that there should be no intermingling of the incoming fresh air with the contaminated air passing to outlet, where the latter is being drawn from the mining area, typically, by reason of exhaust fans or the like. The aforesaid intercomingling of air has been prevented heretofore by the use of permanent barriers, such as those erected from concrete block or the like, which serve to define the passageway for the incoming air.